The use of detection devices for determination, or identification, of particle size is now well known, and such devices have been increasingly capable of determining particles of ever smaller size, including detection and determination of particles in fluids moved at ever increasing flow rates.
Particle detection utilizing scattering of light, such as laser light, in a sensing region, including positioning of the sensing region intracavity, is now commonly used for the detection of particles, and particularly small particles, such as submicron particles, with the light scattered by the particles at the sensing region being collected and detected and the size of the detected small particles being then determined from the size of the scattered light signals (see, for example, U.S. Pat. Nos. 4,571,079, 4,594,715, and 4,798,465).
A laser using an optically pumped, solid state laser medium, and, more particularly, a solid state laser medium, such as, for example, a Neodymium doped (1.1% by weight) Yttrium Aluminum Garnate (Nd:YAG) crystal, within the laser cavity and end-pumped by one or more laser diodes, such as one or more Gallium Aluminum Arsenide (GaAlAs) laser diodes, is shown, for example, in U.S. Pat. Nos. RE 34,729, 4,653,056, 4,723,257 1,739,507, 4,809,291 and 4,872,177, and use of a solid state laser, as above described, has been heretofore developed in conjunction with a sensing region within the laser cavity by Jon C. Sandberg.
Currently available commercial instrumentation based on laser light scattering provides only information on the size distribution and concentration of particles in the sample medium. There is increasing commercial interest, however, in instrumentation that can provide compositional information with respect to detected particles. Knowledge of the composition of detected particles can provide valuable guidance for identifying the source of the particles and/or allow prediction of the impact of a type of particle contamination on a critical manufacturing process. The interest in compositional information is sufficiently great that even rudimentary classification of particles into a few categories would be of significant commercial value.
Devices and/or methods are currently known that utilize lasers for illumination of particles in conjunction with fluorescence, for example, to enable detection of particles (see U.S. Pat. No. 4,281,924), and devices and/or methods are also currently known that utilize infrared emissions to enable identification of unknown chemical species (see U.S. Pat. No. 4,496,839), multi-point pyrometry-based compensated temperature sensing and detection (see U.S. Pat. No. 5,156,461), and analysis of solid material by laser heating of a thin surface layer of the solid material to cause thermal emissions of infrared radiation indicative of characteristics relating to the molecular composition of the solid material (see U.S. Pat. No. 5,075,552).
Thus, while devices and/or methods for detection and/or determination of particles utilizing light scattering, as well as devices and/or methods for heating various items to incandescence for detecting the items or characteristics thereof, are shown in the prior art, the devices and/or methods shown in the prior art are not directed, for example, to particle characteristic determination by detection of resulting light due to illumination of small optically absorbing particles by high intensity light, and/or detection of resulting light that includes both scattered light and emitted light due to heating of optically absorbing particles to a temperature at which a detectable level of incandescent light is emitted.